Add migrations has-pending-model-changes Command

src/EFCore.Design/Design/Internal/MigrationsOperations.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.EntityFrameworkCore.Internal;
+using Microsoft.EntityFrameworkCore.Migrations.Internal;
 
 namespace Microsoft.EntityFrameworkCore.Design.Internal;
 
@@ -242,6 +243,26 @@ public virtual MigrationFiles RemoveMigration(
         return files;
     }
 
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public virtual void HasPendingModelChanges(string? contextType)
+    {
+        using var context = _contextOperations.CreateContext(contextType);
+
+        var hasPendingModelChanges = context.Database.HasPendingModelChanges();
+
+        if (hasPendingModelChanges)
+        {
+            throw new OperationException(DesignStrings.PendingModelChanges);
+        }
+
+        _reporter.WriteInformation(DesignStrings.NoPendingModelChanges);
+    }
+
     private static void EnsureServices(IServiceProvider services)
     {
         var migrator = services.GetService<IMigrator>();

src/EFCore.Design/Design/OperationExecutor.cs

@@ -683,6 +683,40 @@ public ScriptDbContext(
     private string ScriptDbContextImpl(string? contextType)
         => ContextOperations.ScriptDbContext(contextType);
 
+    /// <summary>
+    ///     Represents an operation to check if there are any pending migrations.
+    /// </summary>
+    public class HasPendingModelChanges : OperationBase
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="HasPendingModelChanges" /> class.
+        /// </summary>
+        /// <remarks>
+        ///     <para>The arguments supported by <paramref name="args" /> are:</para>
+        ///     <para><c>contextType</c>--The <see cref="DbContext" /> to use.</para>
+        /// </remarks>
+        /// <param name="executor">The operation executor.</param>
+        /// <param name="resultHandler">The <see cref="IOperationResultHandler" />.</param>
+        /// <param name="args">The operation arguments.</param>
+        public HasPendingModelChanges(
+            OperationExecutor executor,
+            IOperationResultHandler resultHandler,
+            IDictionary args)
+            : base(resultHandler)
+        {
+            Check.NotNull(executor, nameof(executor));
+            Check.NotNull(args, nameof(args));
+
+            var contextType = (string?)args["contextType"];
+
+            Execute(() => executor.HasPendingModelChangesImpl(contextType));
+        }
+    }
+
+    private void HasPendingModelChangesImpl(string? contextType)
+        => MigrationsOperations.HasPendingModelChanges(contextType);
+
+
     /// <summary>
     ///     Represents an operation.
     /// </summary>

src/EFCore.Design/Properties/DesignStrings.resx

@@ -332,6 +332,9 @@ Change your target project to the migrations project by using the Package Manage
   <data name="NonRelationalProvider" xml:space="preserve">
     <value>The provider '{provider}' is not a Relational provider and therefore cannot be used with Migrations.</value>
   </data>
+  <data name="NoPendingModelChanges" xml:space="preserve">
+    <value>No changes have been made to the model since the last migration.</value>
+  </data>
   <data name="NoReferencedServices" xml:space="preserve">
     <value>No referenced design-time services were found.</value>
   </data>
@@ -350,6 +353,9 @@ Change your target project to the migrations project by using the Package Manage
   <data name="NotExistDatabase" xml:space="preserve">
     <value>Database '{name}' did not exist, no action was taken.</value>
   </data>
+  <data name="PendingModelChanges" xml:space="preserve">
+    <value>Changes have been made to the model since the last migration. Add a new migration.</value>
+  </data>
   <data name="PrefixDescription" xml:space="preserve">
     <value>Prefix output with level.</value>
   </data>

src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs

@@ -952,6 +952,39 @@ public static bool IsRelational(this DatabaseFacade databaseFacade)
         => ((IDatabaseFacadeDependenciesAccessor)databaseFacade)
             .Context.GetService<IDbContextOptions>().Extensions.OfType<RelationalOptionsExtension>().Any();
 
+    /// <summary>
+    ///     Returns <see langword="true" /> if the model has pending changes to be applied.
+    /// </summary>
+    /// <param name="databaseFacade">The facade from <see cref="DbContext.Database"/>.</param>
+    /// <returns>
+    ///     <see langword="true"/> if the database model has pending changes
+    ///     and a new migration has to be added.
+    /// </returns>
+    public static bool HasPendingModelChanges(this DatabaseFacade databaseFacade)
+    {
+        var modelDiffer = databaseFacade.GetRelationalService<IMigrationsModelDiffer>();
+        var migrationsAssembly = databaseFacade.GetRelationalService<IMigrationsAssembly>();
+
+        var modelInitializer = databaseFacade.GetRelationalService<IModelRuntimeInitializer>();
+
+        var snapshotModel = migrationsAssembly.ModelSnapshot?.Model;
+        if (snapshotModel is IMutableModel mutableModel)
+        {
+            snapshotModel = mutableModel.FinalizeModel();
+        }
+
+        if (snapshotModel is not null)
+        {
+            snapshotModel = modelInitializer.Initialize(snapshotModel);
+        }
+
+        var designTimeModel = databaseFacade.GetRelationalService<IDesignTimeModel>();
+
+        return modelDiffer.HasDifferences(
+            snapshotModel?.GetRelationalModel(),
+            designTimeModel.Model.GetRelationalModel());
+    }
+
     private static IRelationalDatabaseFacadeDependencies GetFacadeDependencies(DatabaseFacade databaseFacade)
     {
         var dependencies = ((IDatabaseFacadeDependenciesAccessor)databaseFacade).Dependencies;

src/dotnet-ef/Properties/Resources.resx

@@ -228,6 +228,9 @@
   <data name="MigrationsDescription" xml:space="preserve">
     <value>Commands to manage migrations.</value>
   </data>
+  <data name="MigrationsHasPendingModelChangesDescription" xml:space="preserve">
+    <value>Checks if any changes have been made to the model since the last migration.</value>
+  </data>
   <data name="MigrationsListDescription" xml:space="preserve">
     <value>Lists available migrations.</value>
   </data>
@@ -345,4 +348,4 @@
   <data name="WritingFile" xml:space="preserve">
     <value>Writing '{file}'...</value>
   </data>
-</root>
+</root>

src/ef/Commands/MigrationsCommand.cs

@@ -14,6 +14,7 @@ public override void Configure(CommandLineApplication command)
 
         command.Command("add", new MigrationsAddCommand().Configure);
         command.Command("bundle", new MigrationsBundleCommand().Configure);
+        command.Command("has-pending-model-changes", new MigrationsHasPendingModelChangesCommand().Configure);
         command.Command("list", new MigrationsListCommand().Configure);
         command.Command("remove", new MigrationsRemoveCommand().Configure);
         command.Command("script", new MigrationsScriptCommand().Configure);

src/ef/Commands/MigrationsHasPendingModelChangesCommand.Configure.cs

@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.DotNet.Cli.CommandLine;
+using Microsoft.EntityFrameworkCore.Tools.Properties;
+
+namespace Microsoft.EntityFrameworkCore.Tools.Commands;
+
+internal partial class MigrationsHasPendingModelChangesCommand : ContextCommandBase
+{
+    public override void Configure(CommandLineApplication command)
+    {
+        command.Description = Resources.MigrationsHasPendingModelChangesDescription;
+
+        base.Configure(command);
+    }
+}

src/ef/Commands/MigrationsHasPendingModelChangesCommand.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.Tools.Commands;
+
+internal partial class MigrationsHasPendingModelChangesCommand
+{
+    protected override int Execute(string[] args)
+    {
+        using var executor = CreateExecutor(args);
+
+        executor.HasPendingModelChanges(Context!.Value());
+
+        return base.Execute(args);
+    }
+}

src/ef/IOperationExecutor.cs

@@ -37,4 +37,5 @@ IDictionary ScaffoldContext(
     string ScriptMigration(string? fromMigration, string? toMigration, bool idempotent, bool noTransactions, string? contextType);
 
     string ScriptDbContext(string? contextType);
+    void HasPendingModelChanges(string? contextType);
 }

src/ef/OperationExecutorBase.cs

@@ -206,4 +206,9 @@ public string ScriptDbContext(string? contextType)
         => InvokeOperation<string>(
             "ScriptDbContext",
             new Dictionary<string, object?> { ["contextType"] = contextType });
+
+    public void HasPendingModelChanges(string? contextType)
+        => InvokeOperation<string>(
+            "HasPendingModelChanges",
+            new Dictionary<string, object?> { ["contextType"] = contextType });
 }

src/ef/Properties/Resources.resx

@@ -258,6 +258,9 @@
   <data name="MigrationsDescription" xml:space="preserve">
     <value>Commands to manage migrations.</value>
   </data>
+  <data name="MigrationsHasPendingModelChangesDescription" xml:space="preserve">
+    <value>Checks if any changes have been made to the model since the last migration.</value>
+  </data>
   <data name="MigrationsListDescription" xml:space="preserve">
     <value>Lists available migrations.</value>
   </data>
@@ -402,4 +405,4 @@
   <data name="WritingFile" xml:space="preserve">
     <value>Writing '{file}'...</value>
   </data>
-</root>
+</root>

test/EFCore.Relational.Tests/RelationalDatabaseFacadeExtensionsTest.cs

@@ -220,7 +220,7 @@ public void GetMigrations_works()
     private class FakeIMigrationsAssembly : IMigrationsAssembly
     {
         public IReadOnlyDictionary<string, TypeInfo> Migrations { get; set; }
-        public ModelSnapshot ModelSnapshot { get; }
+        public ModelSnapshot ModelSnapshot { get; set; }
         public Assembly Assembly { get; }
 
         public string FindMigrationId(string nameOrId)
@@ -249,6 +249,86 @@ public async Task GetAppliedMigrations_works(bool async)
                 : context.Database.GetAppliedMigrations());
     }
 
+    [ConditionalFact]
+    public void HasPendingModelChanges_has_no_migrations_has_dbcontext_changes_returns_true()
+    {
+        // This project has NO existing migrations right now but does have information in the DbContext
+        var migrationsAssembly = new FakeIMigrationsAssembly
+        {
+            ModelSnapshot = null,
+            Migrations = new Dictionary<string, TypeInfo>(),
+        };
+
+        var testHelper = FakeRelationalTestHelpers.Instance;
+
+        var contextOptions = testHelper.CreateOptions(
+            testHelper.CreateServiceProvider(new ServiceCollection().AddSingleton<IMigrationsAssembly>(migrationsAssembly)));
+
+        var testContext = new TestDbContext(contextOptions);
+
+        Assert.True(testContext.Database.HasPendingModelChanges());
+    }
+
+    [ConditionalFact]
+    public void HasPendingModelChanges_has_migrations_and_no_new_context_changes_returns_false()
+    {
+        var fakeModelSnapshot = new FakeModelSnapshot(builder =>
+        {
+            builder.Entity("Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensionsTests.TestDbContext.Simple", b =>
+            {
+                b.Property<int>("Id")
+                    .ValueGeneratedOnAdd()
+                    .HasColumnType("default_int_mapping");
+
+                b.HasKey("Id");
+
+                b.ToTable("Simples");
+            });
+        });
+        var migrationsAssembly = new FakeIMigrationsAssembly
+        {
+            ModelSnapshot = fakeModelSnapshot,
+            Migrations = new Dictionary<string, TypeInfo>(),
+        };
+
+        var testHelper = FakeRelationalTestHelpers.Instance;
+
+        var contextOptions = testHelper.CreateOptions(
+            testHelper.CreateServiceProvider(new ServiceCollection().AddSingleton<IMigrationsAssembly>(migrationsAssembly)));
+
+        var testContext = new TestDbContext(contextOptions);
+
+        Assert.False(testContext.Database.HasPendingModelChanges());
+    }
+
+    private class TestDbContext : DbContext
+    {
+        public TestDbContext(DbContextOptions options) : base(options)
+        { }
+        public DbSet<Simple> Simples { get; set; }
+
+        public class Simple
+        {
+            public int Id { get; set; }
+        }
+
+    }
+
+    private class FakeModelSnapshot : ModelSnapshot
+    {
+        private readonly Action<ModelBuilder> _buildModel;
+
+        public FakeModelSnapshot(Action<ModelBuilder> buildModel)
+        {
+            _buildModel = buildModel;
+        }
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+            _buildModel(modelBuilder);
+        }
+    }
+
+
     private class FakeHistoryRepository : IHistoryRepository
     {
         public List<HistoryRow> AppliedMigrations { get; set; }